pacman::p_load(maptools, sf, raster, spatstat, tmap)In Class Exercise 4
1 Loading the package
Things to learn outside from this code chunk.
2 Load Dataset
childcare_sf <- st_read("data/geospatial/child-care-services-geojson.geojson") %>%
st_transform(crs = 3414)Reading layer `child-care-services-geojson' from data source
`/Users/school/Documents/GitHub/Week1/lessons/In-class/in-class_ex4/data/geospatial/child-care-services-geojson.geojson'
using driver `GeoJSON'
Simple feature collection with 1545 features and 2 fields
Geometry type: POINT
Dimension: XYZ
Bounding box: xmin: 103.6824 ymin: 1.248403 xmax: 103.9897 ymax: 1.462134
z_range: zmin: 0 zmax: 0
Geodetic CRS: WGS 84
This is already a projected coordinate system. This is converted to meters.
Note
For all spatial analysis, all data must be projected coordinate system.
sg_sf <- st_read(dsn = "data/geospatial", layer="CostalOutline")Reading layer `CostalOutline' from data source
`/Users/school/Documents/GitHub/Week1/lessons/In-class/in-class_ex4/data/geospatial'
using driver `ESRI Shapefile'
Simple feature collection with 60 features and 4 fields
Geometry type: POLYGON
Dimension: XY
Bounding box: xmin: 2663.926 ymin: 16357.98 xmax: 56047.79 ymax: 50244.03
Projected CRS: SVY21
mpsz_sf <- st_read(dsn = "data/geospatial",
layer = "MP14_SUBZONE_WEB_PL")Reading layer `MP14_SUBZONE_WEB_PL' from data source
`/Users/school/Documents/GitHub/Week1/lessons/In-class/in-class_ex4/data/geospatial'
using driver `ESRI Shapefile'
Simple feature collection with 323 features and 15 fields
Geometry type: MULTIPOLYGON
Dimension: XY
Bounding box: xmin: 2667.538 ymin: 15748.72 xmax: 56396.44 ymax: 50256.33
Projected CRS: SVY21
Note
tmap_mode(“plot”) will give a static map
tmap_mode(“view”) will give a interactive map
tmap is an extension of leaflet
alpha is to introduce a certain level of opacity
tm_shape is needed to create a new layer. It needs to be at the start of everyplot
tmap_mode('view')
tm_shape(childcare_sf) +
tm_dots(alph = 0.5, size=0.01) 2.0.1 Converting to Spatial Dataframe
Note
Spatial Polygon has a data table
childcare <- as_Spatial(childcare_sf)
mpsz <- as_Spatial(mpsz_sf)
sg <- as_Spatial(sg_sf)2.0.2 Converting to Spatial Object
Note
This only retains the geometric
childcare_sp <- as(childcare, "SpatialPoints")
sg_sp <- as(sg, "SpatialPolygons")2.0.3 Converting to PPP format
Note
This drops everything else into a list of coordinates that can only be read by the ST package
childcare_ppp <- as(childcare_sp, "ppp")
childcare_pppPlanar point pattern: 1545 points
window: rectangle = [11203.01, 45404.24] x [25667.6, 49300.88] units
3 Additional Map
tmap_mode('view')
tm_shape(childcare_sf) +
tm_dots(alph = 0.5, size=0.01) +
tm_view(set.zoom.limits = c(11,14), set.bounds = TRUE)